HI thank you for your answer so my topic is about the vaporization phenomena of droplet of n-heptane and n decane in the air. i must use CFD (fluent and gambit) to modelize the problem.i did the mesh in gambit, and in fluent, i enter all the operating and bondary conditions, but i don't have a convergence..maybe because i dont know how to use well fluent specially in the injections i ask for your help please if it possible tank you so much